From 32638062d7a028f0d1d72ba27024e42181912a22 Mon Sep 17 00:00:00 2001
From: Jay Dorsey <191564+jaydorsey@users.noreply.github.com>
Date: Fri, 6 Aug 2021 23:09:56 -0400
Subject: [PATCH 1/2] Better error message for missing let

I've run into this problem a number of times. The original error message
is actually a `NoMethodError` and it's not always immediately clear what
the solution is, particuarly if you're new to rspec or rswag

Wanted to see if this kind of behavior is something that the rswag team
would be interested in adopting. I have a few other of these in mind
(will do as small PRs, with tests)
---
 .../lib/rswag/specs/request_factory.rb        | 26 ++++++++++++++++++-
 .../spec/rswag/specs/request_factory_spec.rb  | 15 +++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/rswag-specs/lib/rswag/specs/request_factory.rb b/rswag-specs/lib/rswag/specs/request_factory.rb
index 523b50f..f7b9fce 100644
--- a/rswag-specs/lib/rswag/specs/request_factory.rb
+++ b/rswag-specs/lib/rswag/specs/request_factory.rb
@@ -194,12 +194,36 @@ module Rswag
 
       def build_json_payload(parameters, example)
         body_param = parameters.select { |p| p[:in] == :body }.first
-        body_param ? example.send(body_param[:name]).to_json : nil
+
+        return nil unless body_param
+
+        raise(MissingParameterError, body_param[:name]) unless example.respond_to?(body_param[:name])
+
+        example.send(body_param[:name]).to_json
       end
 
       def doc_version(doc)
         doc[:openapi] || doc[:swagger] || '3'
       end
     end
+
+    class MissingParameterError < StandardError
+      attr_reader :body_param
+
+      def initialize(body_param)
+        @body_param = body_param
+      end
+
+      def message
+        <<~MSG
+          Missing parameter #{body_param}
+
+          Please check your spec. It looks like you defined a body parameter,
+          but did not declare usage via let. Try adding:
+
+              let(:#{body_param}) {}
+        MSG
+      end
+    end
   end
 end
diff --git a/rswag-specs/spec/rswag/specs/request_factory_spec.rb b/rswag-specs/spec/rswag/specs/request_factory_spec.rb
index aff5fb4..a9faef2 100644
--- a/rswag-specs/spec/rswag/specs/request_factory_spec.rb
+++ b/rswag-specs/spec/rswag/specs/request_factory_spec.rb
@@ -160,6 +160,21 @@ module Rswag
             end
           end
 
+          context 'missing body parameter' do
+            before do
+              metadata[:operation][:parameters] = [{ name: 'comment', in: :body, schema: { type: 'object' } }]
+              allow(example).to receive(:comment).and_raise(NoMethodError, "undefined method 'comment'")
+              allow(example).to receive(:respond_to?).with(:'Content-Type')
+              allow(example).to receive(:respond_to?).with('comment').and_return(false)
+            end
+
+            it 'uses the referenced metadata to build the request' do
+              expect do
+                request[:payload]
+              end.to raise_error(Rswag::Specs::MissingParameterError, /Missing parameter comment/)
+            end
+          end
+
           context 'form payload' do
             before do
               metadata[:operation][:consumes] = ['multipart/form-data']

From 86c512f639758dd389769c2c1d8de2c8e93a4f99 Mon Sep 17 00:00:00 2001
From: Jay Dorsey <191564+jaydorsey@users.noreply.github.com>
Date: Fri, 24 Sep 2021 16:11:44 -0400
Subject: [PATCH 2/2] Add single quotes around parameter name

---
 rswag-specs/lib/rswag/specs/request_factory.rb       | 2 +-
 rswag-specs/spec/rswag/specs/request_factory_spec.rb | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/rswag-specs/lib/rswag/specs/request_factory.rb b/rswag-specs/lib/rswag/specs/request_factory.rb
index f7b9fce..eb13b2d 100644
--- a/rswag-specs/lib/rswag/specs/request_factory.rb
+++ b/rswag-specs/lib/rswag/specs/request_factory.rb
@@ -216,7 +216,7 @@ module Rswag
 
       def message
         <<~MSG
-          Missing parameter #{body_param}
+          Missing parameter '#{body_param}'
 
           Please check your spec. It looks like you defined a body parameter,
           but did not declare usage via let. Try adding:
diff --git a/rswag-specs/spec/rswag/specs/request_factory_spec.rb b/rswag-specs/spec/rswag/specs/request_factory_spec.rb
index a9faef2..a26f694 100644
--- a/rswag-specs/spec/rswag/specs/request_factory_spec.rb
+++ b/rswag-specs/spec/rswag/specs/request_factory_spec.rb
@@ -171,7 +171,7 @@ module Rswag
             it 'uses the referenced metadata to build the request' do
               expect do
                 request[:payload]
-              end.to raise_error(Rswag::Specs::MissingParameterError, /Missing parameter comment/)
+              end.to raise_error(Rswag::Specs::MissingParameterError, /Missing parameter 'comment'/)
             end
           end